This week in animal research: w/e 19 September 31 October

Space may make astronauts infertile according to animal experiments, prompting NASA to invest in further mouse studies aboard the ISS and to offer egg and sperm freezing services for its astronauts. Previous studies in rats and mice have shown that exposure to zero gravity can affect male and female reproductive organs. Male rats placed in artificial zero gravity were no longer able to produce sperm during a Russian study conducted in 1979. Radiation exposure in space is also believed to negatively impact on astronaut fertility. Dr Joseph Tash, of the Department of Molecular and Integrative Physiology at the University of Kansas told a conference in Hawaii that there was concern that astronauts could experience the same effects. “We don’t really have the human data to really determine whether what we are seeing in the animals is translatable to humans. But we are seeing big impacts in the animals,” he said.

Stem cells that secrete cancer-killing toxins could be used to treat brain cancer according to new studies in mice. The cells were genetically engineered to secrete large amounts of toxin, which crucially would kill only tumour cells and no others. During the mouse studies the stem cells were surrounded in a gel and placed at the site of a brain tumour after it had been removed. The remaining cancerous cells died. Chris Mason, professor of regenerative medicine at University College London, said: "This is a clever study, which signals the beginning of the next wave of therapies. It shows you can attack solid tumours by putting mini pharmacies inside the patient which deliver the toxic payload direct to the tumour. Cells can do so much. This is the way the future is going to be."

Foetuses of the superb fairy-wren, a beautiful Australian songbird, are capable of distinguishing between the calls of different adult individuals. Scientists played 1 minute recordings to 43 fairy-wren eggs collected from wild nests, including white noise, calls from female fairy-wrens, and calls from a related species. Changes in heart rate in relation to the sound being played showed that the embryos’ brains were engaged in tasks requiring attention, learning and possibly memory. This is the first time that embryonic learning has been seen outside of the human foetus, which can distinguish male from female voices and the voice of their mother from between 32 to 39 weeks.

A potential anti-ageing drug that has been shown to extend mouse lifespans by up to 13% (in females) could be set for a test in pet dogs. Rapamycin is regularly given to human patients as part of an anti-rejection drug cocktail after kidney transplants, but it’s effects on lifespan have not been tested in humans because human lifespans are so long. The proposed trial would be conducted using large dogs with a natural lifespan of eight to ten years, with the treatment beginning at six to nine years of age.

Miniature human stomachs, grown in vitro using human stem cells, appear to respond to infection in the same way as ordinary stomachs creating a new model in which to study human stomach disease. Many human stomach conditions are caused by infections of the bacterium Helicobacter pylori, which does not always cause disease in animal models. “There hasn’t been any good way to study human stomach disease before because animals just don’t get the same diseases,” said James Wells, director of the Pluripotent Stem Cell Facility, Cincinnati Children’s Hospital Medical Center, who led the research.

A new mouse model for Ebola virus has revealed that genetic differences between individuals affect whether the infection is deadly or not. Until now the best animal models for studying Ebola have been monkeys, but they are large, expensive to keep and more dangerous to handle than mice. "Ask any scientist who does this type of work, and you'll hear that they really want non-human primates to be a last resort," said study co-head Angela Rasmussen, of the University of Washington department of microbiology.